This is my attempt at creating a natal chart for the ESA probe Huygens. As in my charts for the Mars rovers, I've used the principles in Luciano Drusetta's article Extraterrestrial Astrology and my own symbols for Saturn's moons.
(A full key to the symbols used in the above diagrams is available.)
Please read the Mars rovers page for a general orientation to extraterrestrial astrology and my methods. This page will mostly describe the differences from those.
The zodiac, astrologically speaking, has nothing to do with the astronomical constellations in the sky. Instead, the sign of Aries begins at the Vernal Equinox and extends for 30 degrees east along the ecliptic. It is followed by the other signs in their traditional order. But what are the "vernal equinox" and the "ecliptic" on Titan? Since Titan is a moon of Saturn, the sun follows a wiggly path across the sky, and since it's orbiting Saturn maybe we should use the "vernal equinox" of Titan's orbit around Saturn? I've chosen to average out the Sun's motion, which yields the ecliptic of the Sun around Saturn. Since the orbits of the major moons of Saturn are only a few degrees from Saturn's equator, I've also chosen to use Saturn's vernal equinox to locate Aries. This has the nice side-effect that all moons of Saturn share the same zodiac, so someone born on Titan at a particular time has the same sun sign as someone born on Iapetus at the same time. (Sun-signs on Saturn are about 2.5 years long.) Saturn's zodiac starts in the astrological sign of Pisces, like Earth's does.
At first I considered using Saturn's path across Titan's sky as the ecliptic, but Titan is tidally locked to Saturn so that path is a point - Saturn sits at one place in the sky and doesn't move. Drusetta suggests marking a stationary body in some way - I chose to circle Saturn's symbol.
Earthly natal charts use the sun, moon, the seven other planets, and Pluto for historical reasons. From Saturn, most of the inner solar system never gets far from the Sun - even Mars is never more than 10° from the sun, so it will always be in conjunction - so I'm not using any of those planets. Of Saturn's many moons, I'm only considering the 8 "major" moons, and the three closest have the same problem with Saturn as the inner planets do with the sun (to a greater or lesser degree). Dione is an edge case (maximum separation of 18°) but I'm including it to bring the number of points back to the traditional 10. For more discussion of this issue, see my Heavenly Bodies to use for Extraterrestrial Astrology page.
I've used landing as birth for the probe, since that time and position are easily available. (Entry into Titan's atmosphere would probably be more appropriate, but I wasn't able to find the latitude and longitude of that event. The landing times (to a precision of 1 minute) and the landing locations (to a precision of thousandths of a degree) can be found at Wikipedia.
The replacement of half of the traditional set of points with moons of Saturn may make any interpretation of this chart impossible. There are a couple of close conjunctions - Jupiter is 1 degree and change from the Medium Coeli, and Dione and Rhea are 2.5 degrees from each other with Rhea in retrograde. Those two conjunctions are in opposition with each other and square to Hyperion's opposition with the Ascendant, forming a Grand Cross. The probe's sun sign is Aquarius, but only 14 minutes from the cusp with Capricorn.
I'd be happy to hear comments on this chart or my methodology. Please don't send any mail attacking or defending astrology in general, or telling me that it's invalid to cast charts for robots - I did this as a fun intellectual exercise.